Spacer



FIG. 1 is a top, front, right-side perspective view of a spacer;

FIG. 2 is a bottom, front, left-side perspective view thereof;

FIG. 3 is a top view thereof, a bottom view thereof being symmetrical to the top view; and,

FIG. 4 is a front view thereof, a back view, a left side view, and a right side view thereof being identical to the front view. 

CLAIM The ornamental design for a spacer, as shown and described. 